Wet etching system for manufacturing semiconductor devices and wet etching method using the same

A wet etching method using a wet etching system for manufacturing semiconductor devices, the wet etching method comprising:

• a) supplying a chemical diluted with deionized water into a tank having a top portion with a cover arranged thereon, the cover having a cooling apparatus arranged therein, and a bottom surface that spans the top portion of the tank from all sides thereof, the entirety of the bottom surface of the cover being sloped, and the chemical comprising phosphoric acid (H3PO4) diluted with deionized water, the concentration of the phosphoric acid (H3PO4) being from 80% to 90%;
• b) placing a semiconductor substrate, having a layer thereon to be etched, into the tank;
• c) driving a heater disposed within the tank to maintain the chemical within a temperature range of about 153° C. to 157° C., whereby the deionized water evaporates;
• d) etching the nitride layer with the phosphoric acid (H3PO4) for about 35 to 40 minutes while the concentration of the phosphoric acid (H3PO4) is maintained substantially at 80% to 90%;
• and
• e) while the nitride layer is being etched, returning the deionized water that has evaporated by operating the cooling apparatus to condense the deionized water on the sloped bottom surface of the cover and thereby cause all of the deionized water that has condensed on the bottom surface of the cover to flow downwardly therealong, whereby the condensed deionized water drops from the bottom surface and the concentration of the phosphoric acid (H3PO4) in the tank is thereby maintained substantially at 80% to 90%.